Nanofiber producing apparatus and method of producing nanofibers

ABSTRACT

According to one embodiment, a nanofiber producing apparatus includes a portion to be deposited, an ejection unit, a power supply unit, an inspection unit and an adjusting unit. The portion to be deposited includes a first surface and a second surface. The second surface faces the first surface. The ejection unit ejects a raw material liquid toward the first surface. The power supply unit generates a potential difference between the ejection unit and the first surface. The inspection unit inspects a defect of the first surface. The adjusting unit is provided so as to face the second surface. The adjusting unit generates a potential in the second surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the Japanese Patent Application No. 2014-180041, filed on Sep. 4, 2014; the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a nanofiber producing apparatus and a method of producing nanofibers.

BACKGROUND

As an apparatus for producing fibrous substances having a diameter in a nanometer unit, a nanofiber producing apparatus has been widely used in a medical field or the like. An electrospinning technology is used for the nanofiber producing apparatus. The electrospinning technology is a technology that charges a raw material liquid, in which a polymer substance or the like is dissolved, and a workpiece and then ejects the raw material liquid toward the workpiece using a potential difference between the raw material liquid and the workpiece. Nanofibers are produced by the raw material liquid being electrically stretched. In such a nanofiber producing apparatus, it is desired that the productivity thereof is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a nanofiber producing apparatus according to a first embodiment;

FIG. 2 is a reference view showing a state in which nanofibers are deposited by a nanofiber producing apparatus;

FIG. 3 is a view showing a state in which nanofibers are deposited by the nanofiber producing apparatus according to the first embodiment;

FIG. 4 is a schematic view showing a nanofiber producing apparatus according to a second embodiment;

FIG. 5 is a schematic view showing a nanofiber producing apparatus according to a third embodiment;

FIG. 6 is a reference view showing a state in which nanofibers are deposited by a nanofiber producing apparatus;

FIG. 7 is a view showing a state in which nanofibers are deposited by the nanofiber producing apparatus according to the third embodiment; and

FIG. 8 is a flowchart showing a method of producing nanofibers.

DETAILED DESCRIPTION

According to one embodiment, a nanofiber producing apparatus includes a portion to be deposited, an ejection unit, a power supply unit, an inspection unit and an adjusting unit. The portion to be deposited includes a first surface and a second surface. The second surface faces the first surface. The ejection unit ejects a raw material liquid toward the first surface. The power supply unit generates a potential difference between the ejection unit and the first surface. The inspection unit inspects a defect of the first surface. The adjusting unit is provided so as to face the second surface. The adjusting unit generates a potential in the second surface.

Hereinafter, each embodiment of the invention will be described with reference to the accompanying drawings.

Further, the drawings are schematic or conceptual so that the relationship between the thickness and the width of each portion and the ratio of the size between portions are not necessarily the same as those of the actual portions. In addition, in a case where the same portion is described, the dimensions or ratios may be different from each other depending on the related drawings.

Further, in the specification of the application and respective drawings, the same elements related to the drawings mentioned before are denoted by the same reference numerals and the detailed description thereof will not be repeated.

First Embodiment

FIG. 1 is a schematic view showing a nanofiber producing apparatus according to a first embodiment.

FIG. 2 is a reference view showing a state in which nanofibers are deposited by a nanofiber producing apparatus.

FIG. 3 is a view showing a state in which nanofibers are deposited by the nanofiber producing apparatus according to the first embodiment.

As illustrated in FIG. 1, a nanofiber producing apparatus 100 includes a power supply unit 10, a control unit 20, an inspection unit 25, an ejection unit 30, an adjusting unit 40, a shielding unit 50, and a portion 60 to be deposited. The direction indicated by an arrow in FIG. 1 is a direction in which the ejection unit 30 ejects a raw material liquid.

In the nanofiber producing apparatus 100 of the embodiment, when a voltage is applied to a space between the ejection unit 30 and the portion 60 to be deposited, the raw material liquid accumulated in the tip portion of the ejection unit 30 by the surface tension is positively (or negatively) charged. Further, the portion 60 to be deposited is charged to have an opposite polarity (or grounded) and the raw material liquid is suctioned by an electrostatic force operating along an electric line of force which is formed toward the portion 60 to be deposited. The voltage applied to the space between the ejection unit 30 and the portion 60 to be deposited is approximately in the range of 10 kV to 100 kV.

When the electrostatic force is larger than the surface tension, the raw material liquid is ejected from a tip portion of the ejection unit 30. The raw material liquid ejected from the tip portion is ejected toward the portion 60 to be deposited. At this time, a solvent contained in the raw material liquid is volatilized and a fiber material of a polymer reaches the portion 60 to be deposited. In this manner, nanofibers N are deposited on the portion 60 to be deposited. The nanofiber producing apparatus 100 of the embodiment forms nanofibers N according to an electrospinning method.

Nanofibers N having a shape of a smooth surface, a porous surface, a bead, a core sheath, a hollow fiber, an ultrafine fiber or the like are deposited on the portion 60 to be deposited by the nanofiber producing apparatus 100. For example, a separator is formed on an electrode of a battery by the nanofiber producing apparatus 100.

The power supply unit 10 is a power supply device that applies a high voltage to a space between the ejection unit 30 and the portion 60 to be deposited. The power supply unit 10 is a power supply device using a DC power supply. For example, one terminal of the power supply unit 10 is electrically connected to the ejection unit 30 and the other terminal of the power supply unit 10 is grounded. Further, one end of the portion 60 to be deposited is grounded. A potential difference can be generated between the ejection unit 30 and the portion 60 to be deposited by such connection.

The control unit 20 is, for example, a computer including a central processing unit (CPU) and a memory. The control unit 20 controls operations of the power supply unit 10 and the ejection unit 30. The control unit 20 is electrically connected to the power supply unit 10 and the ejection unit 30. The control unit 20 controls the power supply unit 10 so as to determine the voltage value to be applied to the ejection liquid. The control unit 20 controls the ejection unit 30 so as to determine the amount of the ejection liquid.

The inspection unit 25 inspects a defect of a first surface 60 a (surface to be deposited) of the portion 60 to be deposited on which the nanofibers N are deposited. For example, as a method of inspecting a defect of the surface, a method of imaging the appearance of the first surface 60 a which is a target for inspection using a camera or the like and observing an image displayed on a display can be exemplified. Further, as another method of inspecting a defect of the surface, a method of imaging the appearance of the first surface 60 a using a camera or the like and specifying the defect of the surface by comparing image data with master data for inspection can be exemplified. In addition, the defect of the surface may be inspected by an inspection object being contacting the first surface 60 a. An inspection device that inspects a defect of the first surface 60 a may be separately provided.

The inspection unit 25 sends information related to the defect of the first surface 60 a to the control unit 20 through a defect signal. The control unit 20 controls the power supply unit 10, the ejection unit 30, the adjusting unit 40, and the shielding unit 50 based on data according to the defect signal from the inspection unit 25. For example, the control unit 20 determines the position of the ejection unit 30 with respect to the portion 60 to be deposited, the position of the adjusting unit 40 with respect to the portion 60 to be deposited, and the position of the shielding unit 50 with respect to the portion 60 to be deposited based on the detected defect on the portion 60 to be deposited.

After the positions of the ejection unit 30, the adjusting unit 40, and the shielding unit 50 are determined, the control unit 20 controls the power supply unit 10 and the ejection unit 30 such that the nanofibers N are formed in the portion having a defect. For example, the control unit 20 determines the voltage value applied by the power supply unit 10 and the amount of the raw material liquid ejected from the ejection unit 30 in order for the nanofibers N to be formed in the portion having a defect. In this manner, the defect on the portion 60 to be deposited is recovered.

The ejection unit 30 is, for example, a nozzle ejecting a raw material liquid which is a material forming the nanofibers N. The ejection unit 30 includes a tip portion and a main body portion. For example, the raw material liquid is accumulated in a tank or the like separately provided from the ejection unit 30 and supplied to the main body portion of the ejection unit 30 from the tank through a pipe. The raw material liquid accumulated in the main body portion is ejected from the tip portion.

The raw material liquid is a liquid that disperses or dissolves a solute serving as a base material of the nanofibers N in a solvent. In addition, the base material liquid is a liquid that is suitably adjusted by the material of the nanofibers N or the properties of the nanofibers N. Examples of the solute that is dispersed or dissolved in the raw material liquid include a resin. Further, examples of the solvent to be used for the raw material liquid include a volatile organic solvent. An inorganic solid material may be added to the raw material liquid.

The adjusting unit 40 is a conductive member. For example, the adjusting unit 40 is an electrode. The adjusting unit 40 may include a power supply device that applies a predetermined voltage. The adjusting unit 40 generates a potential on a second surface 60 b side of the portion 60 to be deposited.

The adjusting unit 40 is arranged in the vicinity of the portion 60 to be deposited. For example, the adjusting unit 40 faces the second surface 60 b of the portion 60 to be deposited. For example, the end portion facing the second surface 60 b of the adjusting unit 40 is pointed. The adjusting unit 40 has a shape in which the width thereof becomes smaller in a direction perpendicular to the direction toward the portion 60 to be deposited from the adjusting unit 40 as the adjusting unit 40 approaches the second surface 60 b of the portion 60 to be deposited.

The adjusting unit 40 changes an electric field generated between the ejection unit 30 and the portion 60 to be deposited and makes a state of the nanofibers N being deposited on the first surface 60 a of the portion 60 to be deposited uniform. For example, the adjusting unit 40 generates a potential (for example, a negative potential) opposite to the potential (for example, a positive potential) generated by the ejection unit 30 on the second surface 60 b side of the portion 60 to be deposited. By generating the opposite potential on the second surface 60 b side, an electric field generated between the ejection unit 30 and the portion 60 to be deposited is changed. That is, a first electric field generated between the ejection unit 30 and the portion 60 to be deposited is changed due to the influence of a second electric field generated from the adjusting unit 40. In this manner, the range in which the nanofibers N are deposited can be controlled.

Moreover, in a case where the portion facing the second surface 60 b of the adjusting unit 40 is pointed, the range in which the nanofibers N are deposited can be narrowed. The first electric field generated between the ejection unit 30 and the portion 60 to be deposited is changed due to the second electric field generated based on the shape of the tip of the adjusting unit 40. For example, in a case where an opening such as a pinhole or the like is generated in a region in which the nanofibers N are deposited, an advancing route of the nanofibers N can be controlled by the second electric field generated based on the shape of the tip of the adjusting unit 40. In this manner, the nanofibers N can be guided even in a case where the opening is small. The uniformity of the film thickness of the nanofibers N can be also improved.

The shielding unit 50 is a conductive member such as a metal. The shielding unit 50 may include a power supply device that applies a predetermined voltage. For example, a predetermined voltage is generated in the shielding unit 50.

The shielding unit 50 is arranged between the ejection unit 30 and the portion 60 to be deposited. In addition, the shielding unit 50 includes three cyclic bodies. The number of cyclic bodies included in the shielding unit 50 may be one, two, or four or more. The range in which the nanofibers N generated from the ejection unit 30 are deposited is controlled by such cyclic bodies.

The shielding unit 50 changes an electric field generated between the ejection unit 30 and the portion 60 to be deposited and makes the state of the nanofibers N being deposited on the first surface 60 a of the portion 60 to be deposited uniform. For example, a potential which is the same as the potential (for example, a positive potential) generated in the ejection unit 30 is generated in the shielding unit 50. By generating the same potential in the shielding unit 50, an electric field generated between the ejection unit 30 and the portion 60 to be deposited is changed. That is, the first electric field generated between the ejection unit 30 and the portion 60 to be deposited is changed due to the influence of a third electric field generated in the shielding unit 50. In this manner, the range in which the nanofibers N are deposited can be controlled.

The advancing route of the nanofibers N is controlled by the electric field generated from the shielding unit 50. For example, in a case where the advancing route of the nanofibers N is controlled by the electric field generated from the adjusting unit 40, the shielding unit 50 can control the advancing route of the nanofibers N with controlling the advancing route of the nanofibers N in the adjusting unit 40. In this manner, the nanofibers N can be guided even in a case where the opening is small. The uniformity of the film thickness of the nanofibers N can be also improved.

The portion 60 to be deposited allows the nanofibers N to be deposited and collected, the nanofibers N being ejected in a space formed between the portion 60 to be deposited and the ejection unit 30. The portion 60 to be deposited includes the first surface 60 a and the second surface 60 b. The first surface 60 a is a surface on the opposite side of the second surface 60 b. The nanofibers N are deposited on the first surface 60 a of the portion 60 to be deposited.

The portion 60 to be deposited is, for example, a substrate. The portion 60 to be deposited may be a sheet-like member. In a case where the portion 60 to be deposited is a sheet-like member, the portion 60 to be deposited may allow the nanofibers N to be deposited and collected in a state of being wound around a roll or the like.

The portion 60 to be deposited may be movable. For example, the portion 60 to be deposited may be a transport device such as a rotating drum, a belt conveyor or the like. The belt conveyor is suitable for mass production of the nanofibers N since the belt can be lengthened.

The nanofiber producing apparatus 100 may be provided with a supply unit that supplies a raw material liquid to the ejection unit 30. Further, a plurality of the ejection units 30 may be provided. The plurality of ejection units 30 are linearly arranged along an arbitrary direction and the raw material liquid can be supplied to each of the plurality of ejection units 30 from the supply unit.

Here, as illustrated in FIG. 2, in a case where a separator of a lithium ion secondary battery is formed, electrodes 64 can be directly coated with the nanofibers N using the nanofiber producing apparatus. A separator is formed on the electrodes 64 as a porous polymer film sheet.

The electrodes 64 are positive or negative electrodes. The electrodes 64 are provided on both surfaces of a collector 65. As the collector 65, foil containing a metal such as aluminum (Al) or the like is used. An electrode body 66 includes the electrodes 64 and the collector 65. For example, the electrode body 66 is placed on the first surface 60 a of the portion 60 to be deposited and the nanofibers N are formed on the electrodes 64. A lithium ion secondary battery is formed by laminating a plurality of such electrode bodies 66 with one another. In a case where the plurality of electrode bodies 66 are laminated with one another, contact between the electrodes (for example, contact between a positive electrode and a negative electrode) is suppressed by the nanofibers N being provided on the electrodes 64.

However, an opening 64 o such as a pinhole is easily generated in a region in which the nanofibers N are deposited. When the opening 64 o is formed on the electrodes 64, there is a concern that the positive electrode is contact with the negative electrode. When the positive electrode is contact with the negative electrode through an opening, a failure such as a short circuit or the like may be generated in the lithium ion secondary battery.

In the nanofiber producing apparatus 100 of the embodiment, the adjusting unit 40 is arranged so as to face the second surface 60 b of the portion 60 to be deposited and changes the electric field generated between the ejection unit 30 and the portion 60 to be deposited. When such an adjusting unit 40 is provided, a state of the nanofibers N being deposited on the first surface 60 a of the portion 60 to be deposited can be uniformized. In this manner, the yield is improved.

For example, as illustrated in FIG. 3, when the adjusting unit 40 is provided so as to face the surface on the opposite side of the surface on which the nanofibers N are deposited, the opening 64 o formed on the electrodes 64 can be filled with the nanofibers N.

According to the embodiment, it is possible to provide a nanofiber producing apparatus with further improved productivity.

Second Embodiment

FIG. 4 is a schematic view showing a nanofiber producing apparatus according to a second embodiment.

As illustrated in FIG. 4, a nanofiber producing apparatus 110 includes a power supply unit 10, a control unit 20, an inspection unit 25, a plurality of ejection units 30 a, a supply unit 35, an adjusting unit 40, a shielding unit 50, and a portion 60 to be deposited.

The portion 60 to be deposited includes a roller 61, a rotating body 62, and a sheet 63. The sheet 63 includes a first surface 63 a and a second surface 63 b. The first surface 63 a is a surface on the opposite side of the second surface 63 b. The direction indicated by an arrow in FIG. 2 is a direction in which the plurality of ejection units 30 a eject a raw material liquid and nanofibers N (not illustrated) are deposited on the first surface 63 a of the sheet 63.

The power supply unit 10 applies a voltage to a substrate 11. The substrate 11 holds the plurality of ejection units 30 a. The substrate 11 is electrically connected with each of the plurality of ejection units 30 a. The plurality of ejection units 30 a are fixed to the substrate 11 in a state in which at least a part of the peripheral surface is in contact with the substrate 11. A voltage supplied from the power supply unit 10 is applied to the plurality of ejection units 30 a by the power supply unit 10, the substrate 11, and the plurality of ejection units 30 a.

The plurality of ejection units 30 a are linearly arranged along the longitudinal direction of the sheet 63. The supply unit 35 supplies a raw material liquid to each of the plurality of ejection units 30 a. For example, the control unit 20 controls the supply unit 35 so as to determine the amount of the raw material liquid ejected from each of the plurality of ejection units 30 a or the amount of the raw material liquid supplied to each of the plurality of ejection units 30 a from the supply unit 35.

The adjusting unit 40 faces the second surface 63 b of the sheet 63 and generates a predetermined potential on the second surface 63 b side. The shielding unit 50 is arranged between the ejection unit 30 a and the sheet 63 and generates a predetermined voltage. An electric field generated between the ejection unit 30 a and the sheet 63 is changed by the adjusting unit 40 and the shielding unit 50 being provided. When the electric field is changed, an opening generated in a region in which the nanofibers N are deposited is filled with the nanofibers N and the state of the nanofibers N being deposited becomes uniform.

A plurality of the adjusting units 40 may be provided. For example, the plurality of adjusting units 40 may be provided so as to correspond to each of the plurality of ejection units 30 a. A plurality of the shielding units 50 may be provided. For example, the plurality of shielding units 50 may be provided so as to correspond to each of the plurality of ejection units 30.

The portion 60 to be deposited allows the nanofibers N to be deposited and transports the nanofibers N. The sheet 63 is wound around the roller 61. The roller 61 rotates so as to wind the sheet 63 by the roller 61 being driven by the rotating body 62. When the roller 61 is driven, the nanofibers N deposited on the sheet 63 are transported in a direction perpendicular to the direction (direction indicated by the arrow) in which the ejection unit 30 ejects the raw material liquid.

In the nanofiber producing apparatus 110 of the embodiment, the adjusting unit 40 is arranged so as to face the second surface 63 b of the sheet 63 and changes the electric field generated between the ejection unit 30 and the portion 60 to be deposited. When such an adjusting unit 40 is provided, the state of the nanofibers N being deposited on the first surface 63 a of the sheet 63 can be uniformized. In this manner, the yield thereof is improved.

According to the embodiment, it is possible to provide a nanofiber producing apparatus with further improved productivity.

Third Embodiment

FIG. 5 is a schematic view showing a nanofiber producing apparatus according to a third embodiment.

FIG. 6 is a reference view showing a state in which nanofibers are deposited by a nanofiber producing apparatus.

FIG. 7 is a view showing a state in which nanofibers are deposited by the nanofiber producing apparatus according to the third embodiment.

As illustrated in FIG. 5, a nanofiber producing apparatus 120 includes a power supply unit 10, a control unit 20, an inspection unit 25, an ejection unit 30, an adjusting unit 40 a, a shielding unit 50 a, and a portion 60 to be deposited. The portion 60 to be deposited includes the first surface 60 a and the second surface 60 b. The first surface 60 a is a surface on the opposite side of the second surface 60 b. The direction indicated by an arrow in FIG. 5 is a direction in which the ejection unit 30 ejects a raw material liquid and nanofibers N are ejected on the first surface 60 a of the portion 60 to be deposited.

The adjusting unit 40 a generates a predetermined potential on the second surface 60 b side of the portion 60 to be deposited. The adjusting unit 40 a faces the second surface 60 b of the portion 60 to be deposited. The adjusting unit 40 a is a rectangular parallelepiped. The adjusting unit 40 a changes an electric field generated between the ejection unit 30 and the portion 60 to be deposited and makes a state of the nanofibers N being deposited on the first surface 60 a of the portion 60 to be deposited uniform.

For example, the adjusting unit 40 a generates a potential (for example, a negative potential) opposite to the potential (for example, a positive potential) generated by the ejection unit 30 on the second surface 60 b side of the portion 60 to be deposited. By generating the opposite potential on the second surface 60 b side, the electric field generated between the ejection unit 30 and the portion 60 to be deposited is changed. That is, a first electric field generated between the ejection unit 30 and the portion 60 to be deposited is changed due to the influence of a second electric field generated from the adjusting unit 40 a. In this manner, the range in which the nanofibers N are deposited can be controlled.

In a case where the state in which the nanofibers N are deposited is not uniform and a portion with an insufficient film thickness is generated, an advancing route of the nanofibers N can be controlled by an electric field generated based on the shape of the adjusting unit 40 a. In this manner, the portion with an insufficient film thickness in the region in which the nanofibers N are deposited can be filled with the nanofibers N. The uniformity of the film thickness of the nanofibers N is improved.

The shielding unit 50 a is arranged between the ejection unit 30 and the portion 60 to be deposited. A predetermined potential is generated in the shielding unit 50 a. The shielding unit 50 a has a shape of two rectangular parallelepipeds and the two rectangular parallelepipeds are provided in a state of facing each other. A width W1 of the adjusting unit 40 a is approximately the same as a width W2 of a space formed by the shielding unit 50 a or smaller than the width W2. The number of the rectangular parallelepipeds included in the shielding unit 50 a may be one or three or more.

The shielding unit 50 a changes an electric field generated between the ejection unit 30 and the portion 60 to be deposited and makes a state of the nanofibers N being deposited on the first surface 60 a of the portion 60 to be deposited uniform. For example, a potential which is the same as the potential (for example, a positive potential) generated by the ejection unit 30 is generated in the shielding unit 50 a. By generating the same potential in the shielding unit 50 a, an electric field generated between the ejection unit 30 and the portion 60 to be deposited is changed. That is, a first electric field generated between the ejection unit 30 and the portion 60 to be deposited is changed due to the influence of a third electric field generated in the shielding unit 50 a. In this manner, the range in which the nanofibers N are deposited can be controlled.

In a case where the state in which the nanofibers N are deposited is not uniform and a portion with an insufficient film thickness is generated, the advancing route of the nanofibers N can be controlled by an electric field generated from the shielding unit 50 a. In a case where the advancing route of the nanofibers N is controlled by the electric field generated from the adjusting unit 40 a, the shielding unit 50 a can control the advancing route of the nanofibers N with controlling the advancing route of the nanofibers N in the adjusting unit 40 a. In this manner, the portion with an insufficient film thickness in the region in which the nanofibers N are deposited can be filled with the nanofibers N. The uniformity of the film thickness of the nanofibers N is improved.

Here, as illustrated in FIG. 6, in a case where a separator of a lithium ion secondary battery is formed, the separator is not formed in the vicinity of a collector 65 projecting from electrodes 64. Further, the nanofibers N are separately coated and the nanofibers N are coated so as to be formed around the end portions of the electrodes 64. In this manner, a portion with an insufficient film thickness of the nanofibers N is easily generated in the vicinity of the end portions of the electrodes 64. That is, a portion 64 d with an insufficient film thickness is easily generated in the vicinity of the end portions of the electrodes 64.

When the portion 64 d with an insufficient film thickness is formed on the electrodes 64, there is a concern that the positive electrode is contact with the negative electrode. When the positive electrode is contact with the negative electrode through the portion 64 d with an insufficient film thickness, a failure such as a short circuit or the like may be generated in the lithium ion secondary battery.

In the nanofiber producing apparatus 120 of the embodiment, the adjusting unit 40 a is arranged so as to face the second surface 60 b of the portion 60 to be deposited and changes the electric field generated between the ejection unit 30 and the portion 60 to be deposited. When such an adjusting unit 40 a is provided, a state of the nanofibers N being deposited on the first surface 60 a of the portion 60 to be deposited can be uniformized. In this manner, the yield is improved.

For example, as illustrated in FIG. 7, when the adjusting unit 40 a is provided so as to face the surface on the opposite side of the surface on which the nanofibers N are deposited, the portion 64 d with an insufficient film thickness which is formed on the electrodes 64 is filled with the nanofibers N.

According to the embodiment, it is possible to provide a nanofiber producing apparatus with further improved productivity.

FIG. 8 is a flowchart showing a method of producing nanofibers.

As illustrated in FIG. 8, a defect of the surface of the portion 60 to be deposited, on which the nanofibers N are deposited, is inspected (Step S110). The inspection unit 25 inspects a defect of the first surface 60 a of the portion 60 to be deposited. The defect of the surface is an opening such as a pinhole or the like, a portion with an insufficient film thickness of the nanofibers N, or the like. In the steps described below, a case in which the defect of the surface is present in the portion 60 to be deposited, on which the nanofibers N are deposited, will be described.

The control unit 20 determines positions of the ejection unit 30, the adjusting unit 40, and the shielding unit 50 based on the position and the kind of the defect on the portion 60 to be deposited (Step S120). The control unit 20 determines the position of the ejection unit 30 with respect to the portion 60 to be deposited, the position of the adjusting unit 40 with respect to the portion 60 to be deposited, and the position of the shielding unit 50 with respect to the portion 60 to be deposited based on the defect on the portion 60 to be deposited. After the positions are determined, the ejection unit 30, the adjusting unit 40, and the shielding unit 50 can be moved in a coordinate axis direction by a driving mechanism or the like.

The control unit 20 may determine at least one position from among the ejection unit 30, the adjusting unit 40, and the shielding unit 50. After the position is determined, at least one of the ejection unit 30, the adjusting unit 40, and the shielding unit 50 can be moved in the coordinate axis direction by the moving mechanism or the like.

The electric field generated between the ejection unit 30 and the portion 60 to be deposited is changed by the electric field generated from the adjusting unit 40 and the shielding unit 50. The advancing route of the nanofibers N is controlled by the electric field generated from the adjusting unit 40 and the shielding unit 50.

The control unit 20 controls the power supply unit 10 and the ejection unit 30 and determines the ejection amount such that the nanofibers N are formed in the portion having a defect (Step S130). The control unit 20 determines the voltage value applied from the power supply unit 10 and the amount of the raw material liquid ejected from the ejection unit 30 in order for the nanofibers N to be formed in the portion having a defect. In a case where the supply unit 35 is provided in the nanofiber producing apparatus 100, the control unit 20 may determine the amount of the raw material liquid ejected from the ejection unit 30 by controlling the supply unit 35.

The raw material liquid is ejected from the ejection unit 30 and the portion having a defect is filled with the nanofibers N (Step S140). In this manner, the defect of the surface on the portion 60 to be deposited is recovered.

According to the embodiment, it is possible to provide a nanofiber producing apparatus with further improved productivity.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions. Moreover, above-mentioned embodiments can be combined mutually and can be carried out. 

What is claimed is:
 1. A nanofiber producing apparatus comprising: a portion to be deposited that includes a first surface and a second surface facing the first surface; an ejection unit that ejects a raw material liquid toward the first surface; a power supply unit that generates a potential difference between the ejection unit and the first surface; an inspection unit that inspects a defect of the first surface; and an adjusting unit that is provided so as to face the second surface, the adjusting unit generating a potential in the second surface.
 2. The apparatus according to claim 1, further comprising a control unit that controls the adjusting unit, wherein the control unit determines a position of the adjusting unit with respect to the portion to be deposited based on a defect signal sent from the inspection unit.
 3. The apparatus according to claim 2, wherein the control unit controls the ejection unit and the power supply unit, and the control unit determines a voltage value applied from the power supply unit and an amount of the raw material liquid ejected from the ejection unit based on the defect signal sent from the inspection unit.
 4. The apparatus according to claim 3, wherein the control unit determines a position of the ejection unit with respect to the portion to be deposited based on the defect signal sent from the inspection unit.
 5. The apparatus according to claim 1, wherein a potential generated in the second surface is a potential whose polarity is opposite to that of the potential generated in the ejection unit.
 6. The apparatus according to claim 1, wherein the adjusting unit has a shape whose width is decreased as the adjusting unit approaches the second surface.
 7. The apparatus according to claim 1, wherein an end portion facing the second surface of the adjusting unit is pointed.
 8. The apparatus according to claim 1, wherein the adjusting unit has a shape of a rectangular parallelepiped.
 9. The apparatus according to claim 1, further comprising a shielding unit that is provided between the ejection unit and the first surface, the shielding unit generating a predetermined potential, wherein the potential generated in the shielding unit is a potential whose polarity is the same as that of the potential generated in the ejection unit.
 10. The apparatus according to claim 9, further comprising a control unit that controls the shielding unit, wherein the control unit determines a position of the shielding unit with respect to the portion to be deposited based on a defect signal sent from the inspection unit.
 11. The apparatus according to claim 9, wherein the shielding unit includes at least one circular body provided so as to surround the defect.
 12. The apparatus according to claim 9, wherein the shielding unit includes a pair of rectangular parallelepipeds provided so as to face each other in order to surround the defect, and the width of the adjusting unit is approximately the same as the width between the rectangular parallelepipeds or smaller than the width between the rectangular parallelepipeds.
 13. The apparatus according to claim 1, wherein the ejection unit includes a plurality of nozzles, and the apparatus further comprises a supply unit that supplies the raw material liquid to each of the plurality of nozzles.
 14. A nanofiber producing apparatus comprising: a portion to be deposited that includes a first surface and a second surface facing the first surface; a plurality of ejection units that eject a raw material liquid toward the first surface; a power supply unit that generates a potential difference between the plurality of ejection units and the first surface; an inspection unit that inspects a defect of the first surface; and a plurality of adjusting units that are provided so as to face the second surface, each of the adjusting units corresponding to each of the ejection units, the adjusting units generating a potential in the second surface.
 15. The apparatus according to claim 14, wherein a potential generated in the second surface is a potential whose polarity is opposite to that of the potential generated in the plurality of ejection units.
 16. The apparatus according to claim 14, further comprising a plurality of shielding units that are provided between the plurality of ejection units and the first surface, each of the shielding units corresponding to each of the ejection units, the shielding units generating a predetermined potential, wherein the potential generated in the shielding units is a potential whose polarity is the same as that of the potential generated in the plurality of ejection units.
 17. A method of producing nanofibers that uses a nanofiber producing apparatus which allows a power supply unit to generate a potential in an ejection unit and allows the ejection unit to eject a raw material liquid so as to deposit nanofibers on a portion to be deposited, the method comprising: inspecting a defect of a surface to be deposited of the portion to be deposited; determining a voltage value applied from the power supply unit and an amount of the raw material liquid ejected from the ejection unit based on the defect; and depositing the nanofibers on the defect by generating a potential in a surface on the opposite side of the surface to be deposited.
 18. The method according to claim 17, further comprising determining a position of the ejection unit with respect to the portion to be deposited based on the defect.
 19. The method according to claim 17, wherein a potential generated in the surface on the opposite side of the surface to be deposited is a potential whose polarity is opposite to that of the potential generated in the ejection unit.
 20. The method according to claim 17, wherein the depositing of the nanofibers on the defect includes generating a potential whose polarity is the same as that of the potential generated in the ejection unit between the ejection unit and the surface to be deposited. 